US3713077A

US3713077A - Quick make and break plug-in connector for a high voltage and high current circuit

Info

Publication number: US3713077A
Application number: US00100677A
Authority: US
Inventors: M Leonard
Original assignee: Westinghouse Electric Corp
Current assignee: ABB Inc USA
Priority date: 1970-12-22
Filing date: 1970-12-22
Publication date: 1973-01-23
Anticipated expiration: 1990-01-23

Abstract

A connector for a high voltage and high current circuits comprising a stationary contact member and a plug-in contact member with means for causing said plug-in contact member to quickly engage or disengage said stationary contact member in making or breaking the circuit comprising said fixed and plug-in contact members.

Description

United States Patent Leonard 51 Jan. 23, 1973 I5 QUICK MAKE AND BREAK PLUG-IN i561 References Cited CONNECTOR FOR A HIGH VOLTAGE UNITED STATES PATENTS AND HIGH CURRENT CIRCUIT 52 7 1/1925 B 3 l 1, 2,5 4 en'amin 39 H1 lnvemofl Merrill Lw'lald, Fowler, Ohlo 3,542,986 11/1970 Kots ki ..200 149 A W 3,314,041 4 1967 Potterin.... .....339 91 R [73] Asslgnee' ga t g Elem corporat'on 1,736,887 11/1929 Pritchett... ..339/46 5 2,223,975 12/1940 Traver ..200/149A 22 Fil d; 22, 1970 2,830,151 4/1958 Hill .1 ..200 149 R X 3,509,516 4/1970 Phillips ..339/111 21 Appl. No.: 100,677

Primary Examiner-Richard E. Moore Related U'S' Apphcanon Data Att0rney-A. T. Stratton and F. E. Browder [62] Division of Ser. No. 774,908, Nov. 12, 1968, abandoned. [57] ABSTRACT 52 us. c1. ..339/111, 339/45 R, 339/60 R A Connector for a high voltage and high current [51] Int. Cl. ..I-I0lr 13/52 cuiis comprising a stationary Contact member and a [58] Field of Search 339/62, 65, 111, 45, 46, 255 plug-in contact member with means for causing said plug-in contact member to quickly engage or disengage said stationary contact member in making or breaking the circuit comprising said fixed and plug-in contact members.

5 Claims, 10 Drawing Figures QUICK MAKE AND BREAK PLUG-IN CONNECTOR FOR A HIGH VOLTAGE AND HIGH CURRENT CIRCUIT CROSS REFERENCE TO RELATED APPLICATION This application is a division of application Ser. No. 774,908 filed Nov. 12, 1968, now abandoned, which is assigned to the same assignee as the present application.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to quick make and break plugin connectors for connecting a high voltage and high current circuit and more particularly for connecting a distribution transformer, or other electrical apparatus, in the circuit.

2. Description of the Prior Art In the prior art plug-in connectors for connecting distribution transformers, or other electrical apparatus, into a distribution circuit, the connector usually comprises a stationary female element and a plug-in male or movable element. The plugging of the movable element into the fixed element usually is obtained with a sliding motion and there is no definite indication to the operator as to when proper electrical connection has been made between the two plug-in elements. This lack of indication as to when a proper electrical connection has been made between the two elements sometimes results in improper connections which are inoperative and sometimes results in undue forcing of the elements which could cause damage to the connector.

Accordingly, it is a main object of this invention to provide a plug-in type connector comprising a hollow stationary contact and a movable plug-in contact with means for causing the contacts to engage with a snap action when the movable contact is plugged into the stationary contact. This snap action gives the operator a definite feel when the proper connection has been made.

SUMMARY OF THE INVENTION This invention comprises a plug-in type connector for connecting a distribution transformer, or other electrical apparatus, into a high voltage, high current circuit. As an example the circuit could be of the order of 7,200 volts with 200 or more amperes of load current and as much as 10,000 amps. short circuit current, depending upon the circuit itself as well as the power system feeding the circuit. The connector comprises a stationary element having an electrical contact and a movable or plug-in element having an electrical contact which plugs into a stationary element and makes electrical contact with the contact of the stationary element. The connector includes spring means or other energy storage means for causing the movable contact to engage the stationary contact with a snap action when the connection between the two parts of the connector are made. The connector also includes energy storage means which causes the movable contact to separate from the fixed contact with a quick action when the two parts of the connector are separated to break the circuit. The snap action when the contacts are made or broken eliminates the possibility of drawing long time duration are and generating a large quantity of arc gas products when the two parts of the connector are engaged or disengaged to make or break a circuit, and the snap action also gives the operator a definite feel as to when the circuit between the stationary contacts and the movable contact has been properly made or properly broken. The connector also includes a gas storage space for cooling hot gases which may be generated by an arc. This prevents the hot are products from building up sufficient pressure to blow the connector apart. This connector possesses a distinctive advantage over the prior art connectors in that a definite snap action indicates to the operator when the two parts of the connector are properly engaged to make a circuit and also when they have been disengaged to break a circuit. The connector also includes arc quenching material which generates a gas in the presence of an arc to assist in extinguishing the arc. This arc quenching material may be of the type disclosed in US. Pat. No. 3,059,081 or U.S. Pat. No. 3,027,352.

In a plug-in type of connector it is easy to break the circuit, but difficult to close the circuit. The reason for this is that the connector will never be opened on fault; but, it is rather likely to be closed on fault. Consequently, it is desired that the connector close the circuit with a definite snap action. Although a snap open action is also desired, in this type device the snap open action is not as important as the snap close action for the reason just given.

In normal design practice a switch or circuit breaker that snaps closed snaps all the way, and this whole travel is out of control of the operator. However, this type of action is virtually impossible with a plug-in type of connector that an operator holds on the end of a hook stick. This invention accomplishes the snap action result by providing a very short travel of the contacts during the snap action; the actual distance of travel is determined by the voltage on the system. It is apparent that an arc must not strike between the contacts before the snap action begins; this is the tendency with present designs of plug-in connectors and is the reason they sometimes explode. Therefore, the contact separation in the connector of this invention 'just before the snap-action starts is at least a little more than the breakdown voltage of air at the line voltage. This distance is about one-tenth inch for circuits in which the connector of this invention is commonly used.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of one embodiment of the plug-in connector provided by this invention;

FIG. 2 is a sectional view of a second embodiment of the connector provided by this invention;

FIG. 3 is a cross-sectional detail showing another spring arrangement which may be used in the connector in place of the spring arrangement shown at line III-III of FIG. 2;

FIG. 4 is a sectional view of a still further embodiment of this invention;

FIG. 5 is a cross-sectional view taken along line V- V of FIG. 4 illustrating the electrical contacts in the closed position;

FIG. 6 is a cross-sectional view taken along the line V--V of FIG. 4 illustrating the position of the electrical contacts during the process of separating the two parts of the connector;

FIG. 7 is a sectional view of a still further embodiment of this invention;

FIG. 8 is a sectional view of still another embodiment of this invention;

FIG. 9 is a detail of the latch arrangement of FIG. 8 showing the position of the latch when the contact elements are in circuit closed position; and

FIG. 10 is a detailed view of another embodiment of a latch arrangement which may be used in the connector shown in FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Throughout the description which follows like reference characters indicate like parts in all of the various figures of the drawings.

Referring specifically to FIG. 1 of the drawings, this figure illustrates a plug-in type connector comprising a first or stationary part 10 and a second or plug-in part 12.

The first or stationary part 10 of the connector comprises a body portion 14 which may be made of rubber or any other suitable moldable material. The body portion 14 has a central opening 15 therein with an electrical contact element 16 located in the opening 15. The contact element 16 comprises a pair of spring fingers 18. These spring fingers 18 are attached to a screw threaded portion of the contact 16 to which a high voltage cable 20 is attached. The body portion 14 of the element 10 also has a circumferential depression 22 formed therein beyond the hook-shaped ends 18 of the contact fingers 18. A sleeve 24 of material which generates gas which assists in extinguishing any are which may occur, is screw-threaded into the end of the body portion as indicated at 26.

The second or plug-in portion 12 of the connector comprises a body portion 30 which is also molded from rubber, or some other suitable moldable material which stores energy when force is applied thereto. The body portion 30 has a connector 32 therein for connecting to the high voltage cable circuit, such as the circuit 20. Attached to the connector 32 is a plug-in contact member 34 which carries at its inner end thereof a plug of arc quenching material 36. The plug-in contact element 34 also has an opening-37 therein in which is placed a detent 38, which detent is forced outwardly by a coil spring 40.

The plug of arc quenching material 36 has a cam surface 42 on the lower end thereof.

When the plug-in contact element 34 of the movable member 12 is inserted into the opening 15 in the body 14 of the stationary element 10 to make an electrical connection between the contact fingers 18 of the stationary member 10 and the contact element 34 of the movable member 12, the detent 38 will be obstructed or will tend to be prevented from entering the sleeve 24 of the stationary element 10. The body portion 30 of the movable element 12 being made of rubber or other compressible materials, as the operator pushes on the body portion 30 of the movable element 12 to overcome the force of the spring 40, the detent 38 will enter the opening in the fixed element 10, and slide along the inside wall thereof. This action will occur with a snap action as soon as the detent 38 enters the opening in the sleeve 24 because of the energy stored in the rubber body portion 30. An eye 44 for a hook stick is provided for the operator to apply force to the body portion 30 of the movable element 12 to cause the contacts to engage or disengage. This force will cause the detent 38 to enter the opening in the sleeve 24 and rapidly move along the central opening 15 in the body portion 14 of the stationary element 10 until the detent reaches the depression 22 in the body portion 14 of the element 10. As the detent 38 reaches the depression 22, the detent 38 will quickly snap into the depression 22 and the contact member 12 will have moved downward sufficiently for the hook ends .18 of the contact fingers 18 to pass over the arc quench plug 36 and make electrical contact with the contact member 34 of the element 12. The cam surface 42 of the quench plug 36 merely facilitates starting of the quench plug 36 in between the contact fingers 18 when the movable or plug-in contact 34 is plugged into the stationary element to make electrical contact.

There is a slight clearance 45 between the over-hanging cap of the movable element 12 and the head of the stationary element 10 which permits easy insertion of the contact 34 in between the contact fingers 18 of the stationary member 10. After contact has been made between the two elements, a hose clamp 46 is tightened around the cap of the portion 30 of the movable element 12 to drive out all air between the interfaces of the two parts of the connector.

Some arcing may still occur when the connection is being made and therefore a space 48 in the central bore in the stationary element 10 is provided to collect the gaseous arc products and permit them to cool before building up sufficient pressure to blow the movable part 12 of the connector away from the stationary part 10.

When the movable part 12 of the connector is removed from the stationary part 10 to break the circuit formed by the contact fingers 18 of the stationary part 10 and the contact element 34 of the movable part 12, the operator merely pulls on the eye 44 of the body portion 30 of the movable part of the connector with a hook stick. This pulling on the eye 40 will store energy in the rubber, or other energy storage material, of which the body portion 30 is made. When this stored energy becomes high enough it will cause the detent 38 to snap out of the depression 22 and the two

parts

10 and 12 of the connector will separate with a snap ac,- tion.

The connector shown in FIG. 2 is similar to that shown in FIG. 1, except that a different arrangement is provided for causing the snap action between the contact fingers 18 of the fixed part of the connector and the contact element 34 of the movable part of the connector. In this embodiment the arc quench plug 36 is of larger diameter than the contact element 34 and is attached to the lower end of the contact element 34 by being screw threaded thereon as indicated'at 50. The

are quench plug 36 of this embodiment has a cam surface 52 at its upper end and also a cam surface 54 at its lower end. The spring contact fingers 18 of the fixed element 10 of this embodiment are surrounded by a circular coiled spring 56 which applies pressure to the contact fingers 18 which tend to keep them closed. When it is desired to make electrical contact between the spring fingers 18 of the fixed element 10 and the contact element 34 of the movable element 12 the quench plug 36 is inserted into the top of the central opening of the fixed element 10 and pushed downward. The lower cam surface 54 of the quench plug 36 will open the spring fingers 18 against the force of the spring 56 and permit the quench plug 36 to pass downwardly between the spring fingers 18. When the cam surface 52 of the upper end of the quench plug 36 reaches the upper end of the spring fingers 18 the hook ends 18' of the spring fingers 18 will quickly slide off the cam surface 52 and make contact with the contact element 34 of the plug-in member 12 due to the energy stored in the rubber body member 30 of the element 12. a

When it is desired to break the circuit between the contact fingers 18 of the fixed element 10 and the contact 34 of the movable element 12 the operator pulls on the eye 44 of the movable element 12 and the energy stored in the rubber in this pulling causes the member 12 to move away from the member 10; and, as it does so the upper cam surface 52 of the quench plug 36 wedges the spring fingers 18 apart to permit the quench plug 36 to pass between the hook ends 18' of the spring fingers l8 and break the electrical circuit. As the lower cam surface 54 of the quench plug 36 moves from between the spring fingers 18 there is a snap action due to the energy stored in the rubber of the body portion 30 of the movable element 12.

FIG. 3 shows a detail of another spring arrangement which could be used in place of the spring 56 shown at line III-III in FIG. 2. As shown in FIG. 3 the spring arrangement for this embodiment comprises two coil springs 60 which would apply a compressive force to the fingers 18 through members 62 joining the ends of the two springs 60. This arrangement could comprise a single continuous element comprising the two springs 60 with straight parts 62 between the two springs. This arrangement tends to apply a force to the spring fingers 18 which tends to force the spring fingers 18 together. In all other respects the device of FIG. 3 operates the same as the device of FIG. 2.

Referring specifically to FIG. 4, which shows another embodiment of this invention, in this embodiment the contact element carried in the central opening of the body portion of the stationary member 10 comprises a pair of spring fingers 18 having hook portions 18'.

The electrical contact element 34 of the movable plug-in member 12 has attached thereto by means of a pin 64 a plug 63 of arc quench material. The pin 64 is carried by the contact element 34 and it is free to move up and down in a slot 65 in the quench plug 63. The upper end of the quench plug 63 comprises a plurality of spline fingers 69. Also carried on the contact member 34 is a slidable spline 67 having fingers 68 which lie between the fingers 69 on the quench plug 63. The slidable spline 67 is movable on the contact element 34 with respect to the quench plug 66. The upper end of the fingers 68 of the spline 67 are cam shaped as indicated at 70. In this embodiment when the movable contact member 34 is inserted into the stationary element 10 to make electrical contact between the spring fingers 18 in the movable contact element 34, as the contact element 34 is forced into the central opening of the element 10 the cam surface 54 on the quench plug 62 will open the spring fingers l8 and permit the quench plug 62 to pass between the ends of the spring fingers 18. As the quench plug 63 passes between the spring fingers 18 to a point where the hook ends 18' of the spring fingers 18 will snap off the spline fingers 69 and engage the contact member 34 to make electrical connection between the contact member 34 and the spring fingers 18. The spring fingers l8 snap over the ends of the spline fingers 69 with a snap action.

To break the contact between the spring fingers 18 of the fixed element 10 and the contact 34 of the movable element 12 the operator pulls. on the eye 44 of the movable member 12 and this causesthe pin 64 to move upward in the slot 65 until it reaches its upper travel, then the pin 64 causes the quench plug 63 to move upwardly, and as it moves upwardly the spline 67 also moves upwardly and the sloping cam surface of the spline fingers 68 forces the upper ends of the spring fingers 18 apart and raises and separates the upper ends of the spring finger 18 to permit the spline fingers 69 on the quench plug 63 to pass between the upper ends 18 of the spring finger 18.

It is seen from this embodiment that the spline fingers 69 and the hook portions 18" on thespring fingers 18 provide a positive locking action of the connection when it is in closed circuit condition to prevent the contacts 18 I and 34 from becoming separated until the spline 67 has been moved sufficiently upward to cause the cam surface 70 of the movable spline 67 to separate the hook portions 18 of the spring fingers '18 a sufficient distance to permit the spline fingers 69 to pass between the hook portions 18' of the spring fingers.

When the circuit is opened by removing the movable contactelement 34 from the central opening in the stationary contact element 12 the lower cam surface 54 on the quench plug 63 will pass between the hook portions 18' of the contact fingers 18 with a rapid movement due to the energy stored in the rubber of the body portion 30 of the stationary element 12 by pulling on the eye 44 with a hook stick.

FIG. 5 is a detail taken along line V--V of FIG. 4 illustrating the position of the hook portions 18' of the spring finger contact elements 18 and the

spline fingers

68 and 69 when the contact element 34 is in circuit making relationship with the spring fingers l8. 7

FIG.. 6 is a detailed sectional view'taken along line V-V showing the relative positions of the hook por tions 18" of the spring fingers l8 and the spline fingers 69 when the hook portions 18' of the spring fingers 18 are out of contact with the contact element 34.

- FIG. 7 illustrates a still further embodiment of this invention which provides a snap action when the contacts of the connector are made and broken. In this embodiment the stationary element 12 comprises a pair of spring finger contacts 18. The movable element 12 comprises a contact element 34 having an enlarged end portion 72. The enlarged end portion 72 of the contact 34 has a cam portion 74 at its upper end. The enlarged portion 72 of the contact member 34 has a slot 76 therein. A hollow cylindrical arc quenching member 78 surrounds the enlarged portion 72 of the contact member 34 and is pinned thereto by a pin 80 which moves in the slot 76. The lower end of the arc quenching member 78 also has a cam surface 82 provided thereon. In this embodiment, when the movable contact element 34 is inserted into the cylindrical bore of the stationary contact element 10 to make electrical contact between the element 34 and the spring fingers 18 of the stationary element 10, the cam surface 82 of the arc quench member 78 enters between the hook portions 18' of the spring fingers 18 and forces them apart to permit the quench member 78 to pass between the spring fingers 18. When the quench member 78 has passed beyond the hook ends 18' of the spring fingers the spring fingers 18 snap onto the contact member 34 with a snap action. In this embodiment it is seen that the underside of the hook portions 18' of the spring fingets 18 also has a cam surface 84. When it is desired to break the connection between the contact member 34 and the spring fingers 18, the operator merely pulls on the eye 44 of the movable member 12 and this causes the enlarged portion 72 of the contact member 34 to move upwardly until the bottom of the slot 76 picks up the pin 80 and by this time the cam surface 74 on the enlarged portion 72 has wedged against the cam surface 84 on the underside of the hook portions 18' of the spring fingers 18 to cause the hook portions 18 of the spring fingers 18 to separate sufficiently to permit the quench member 78 to engage the camsurface 84 and then pass through the hook portions 18 of the spring fingers 18. It is seen that the hook portions 18 of this embodiment by engaging with the upper ends of the quench member 78 provides a definitely locked connection when the contacts 34 and the hook portions 18 of the spring fingers 18 are in engagement, which prevents opening of the circuit until the cam portion 74 of the enlarged member 72 has been moved upwardly far enough to engage the cam surfaces 84 on the hook portions 18' to separate the contact fingers 18 to permit the upper end of the quench member 78 to pass between the hook portions 18' of the spring fingers 18. This embodiment of the invention provides a connection which gives a snap action upon engagement of the contacts 30 and the spring fingers 18.

Referring specifically to FIG. 8 which shows a still further embodiment of this invention, the movable element of this embodiment contains a contact member comprising a central member 90 connected to the electrical conductor 32. The central element 90 has attached thereto and surrounding the element 90 an arc quench plug 92 which is screw threaded to the end of an electrical contact element 94. The electrical contact element 94 is hollow as indicated at 96, and positioned in the hollow space 96 and surrounding the element 90 is a coil spring 93 which is retained in position by a stop 98 and the lower end of the hollow portion 96. A latch member 100 is pivoted to the upper end of the contact member 94 as indicated at 101. A latch trip member 102 is carried by the central member 90. The lower end of the quench plug 92 has an elongated slot 104 therein and the assembly comprising the quench plug 92 and the contact member 94 is pinned to the central member 90 by a pin 106 which may move up and down in the slot 104. An electrical shunt 108 electrically connects the central member 90 to the electrical contact member 94. In this embodiment of the invention when it is desired to connect the contact element 94 to the spring fingers contacts 18 of the stationary member 10, the quench plug 92 is positioned in the central opening in the stationary element 10 and the operator pushes down on the movable element 12 at the eye 44. This causes the cam surface 93 of the quench plug 92 to separate the hook portions 18 of the spring finger contacts l8 and permit the quench plug 92 to pass between the spring finger contacts 18. As the operator continues to push onto the eye 44 the latch member engages the upper surface of the stationary member 10 as indicated at 110 and prevents the contact element 94 from moving down to a position where it will contact the hook portions 18' of the spring fingers 18, but as the operator continues to push on the eye 44 the spring 93 is compressed and the latch trip member 102 moves downward and strikes the upper portion 12 of the latch member 100 and causes the lower portion of the latch member to pivot to a position as shown in FIG. 9. When this happens the spring 93 being compressed or loaded, rapidly snaps the contact element 94 downwardly between the hook portions 18' of the spring fingers 18. With the contact 94 in engagement with the spring finger contacts 18 the latch 100 pivots into the central opening 96 of the contact element 94 as shown in FIG. 9.

When it is desired to open the circuit comprising the spring fingers 18 and the contact 94 the operator merely pulls on the eye 44 to withdraw the assembly comprising the quench plug 92 and the contact element 94 from the central opening of the stationary element 10.

FIG. 10 is a detail of a second embodiment of the latching arrangement to be used with the connector shown and described in connection with FIG. 8. In this embodiment a latch is provided which engages the upper surface of the fixed member 10 at 122 and a release pin 124 is provided on the central member 90. The release pin 124 engages a cam portion 126 of the latch 120 to cause the latch to disengage from the upper surface 122 of the element 10 and snap into the central portion 96 of the contact member 94 to permit the contacts to engage with a snap action in the same manner as described in connection with FIG. 8.

From the foregoing it is seen that this invention has provided an improved plug-in type connector for a high voltage and high current circuit wherein electrical connection between the stationary and the plug-in portion of the connector is made with a snap action when the two parts are connected together to make the circuit. This comprises a substantial improvement over prior art devices of this type which give no definite indication or feel to the operator when the circuit has been made or when it has been broken.

I claim as my invention:

1. A plug-in type of connector for a high voltage and high currect conductor, said connector comprising a first contact structure comprising a hollow member having a plurality of elongated spring finger contact members mounted therein to provide a hollow contact member, a second electrical contact member adapted to be plugged into said hollow contact member, said second electrical contact member having a member comprising arc-extinguishing material attached thereto, said member comprising arc-extinguishing material having a first cam shape surface at a first end thereof for engaging end portions of said spring finger contact members to open said spring finger contact members to facilitate insertion of said second contact member into the hollow provided by said spring finger contact members, means forming a second end of said member comprising arc extinguishing material to assist in opening said spring finger contact members to facilitate removal of said second contact member from said hollow contact structure provided by said spring contact members, and means causing said spring finger contact members to engage said second contact structure with a snap action when said second contact member is plugged into the hollow contact structure provided by said spring finger contact members.

2. The connector of claim 1 wherein said means to assist in opening said spring finger contact members to facilitate removal of said second contact member from said hollow provided by said spring contact members comprises a second cam shaped surface on a second end of said member comprising arc-extinguishing material.

3. The connector of claim 1 wherein said means causing said spring finger contact members to engage said second contact structure with a snap action when said second contact member is plugged into the hollow contact structure provided by said spring finger contact members comprises a second cam shaped surface on a second end of said member comprising arc extinguishing material and additional spring means acting on said spring finger contacts.

4. The connector of claim 3 wherein said additional spring means comprises a pair of tension springs connected to apply force to said spring finger contact members.

5. The connector of claim 3 wherein said additional spring means comprises a closed loop coil spring located in said hollow member and surrounding said spring finger contact members and applying force to said spring finger contact members.